1. Field of the Invention
This invention relates to a method and apparatus for correcting perceived imperfections and aberrations in the optical and mechanical systems of a scanning laser system. In particular, the present invention adjusts the profile of a laser spot in a scanning laser system.
2. Description of Related Art
U.S. Pat. No. 5,233,367 to Curry, discloses a multi-beam interlaced scanning system and its disclosure is herein incorporated by reference.
In such scanning laser systems, it is sometimes necessary or desired to correct for perceived imperfections in the spot profile or to correct for aberrations in the optical and mechanical systems used to scan the spot. U.S. Pat. No. 5,233,367 suggests that a uniform scan may be obtained by varying the spot size. Typically, it is difficult and expensive to design an optical source or system which can generate several beams which are adjustable in intensity and spaced so as to overlap. A multibeam laser diode has the desired adjustability, but the spacing is such that the imaged sources do not produce overlapping spots. An optical system which alters the trajectory of the beams so that they overlap would be expensive as it would be utilizing separate sources, either gas or diode, and optically combining them so that they overlap. Slanting sources in a multibeam ROS would sere to simulate the overlapping of spots in the process direction, but would introduce a start of scan jitter error as well as slanting individual spots aspect ratio. U.S. Pat. No. 5,233,367 does not disclose a method for performing correction to imperfection in spot profile and system caused aberrations.